Corrugated paperboard edge sealing and slitting apparatus

ABSTRACT

Apparatus for providing an improved sheet of corrugated paperboard wherein an extended edge portion of one of the liner layers is folded over the edge of the fluted medium and the other liner layer and adhesively sealed to the other liner layer while the opposite edge of the paperboard is being slit at a desired width. The apparatus is adapted to clamp to the support bars on a corrugator slitter to permit edge folding and sealing during a continuous corrugating process. This mechanism provides dimensional stability in that an edge folding plow and slitter are tied together and mounted by means of spring-loaded double hinges that apply the necessary pressure to the folding edge and permit the apparatus to follow the edge of the sheet when weave occurs.

limited States Patent [72} Inventors [21 1 Appl. No. [22] Filed [45] Patented [73] Assignee [54] CORRUGATED PAPERBOARD EDGE SEALING AND SlLlTTllNG APPARATUS 3 Claims, 4 Drawing Figs.

[52] US. Cl 156/479, 156/205,l56/259, 156/271 [51] Int. Cl B311 1/22 [50] Field of Search 156/202,

[56] References Cited UNITED STATES PATENTS 2,781,818 2/1957 Beckman et a1, 156/202 3,031,356 4/1962 Bousquet et a1. 156/202 3,044,534 7/1962 Yoho 156/202 X 3,307,995 3/1967 Martin, Sr. 156/271 X Primary Examiner-Benjamin A. Borchelt Assistant Examiner-1G. E. Montone Attorneys-Alan J1 Steger and E. J. Holler ABSTRACT: Apparatus for providing an improved sheet of corrugated paperboard wherein an extended edge portion of one of the liner layers is folded over the edge of the fluted medium and the other liner layer and adhesively sealed to the other liner layer while the opposite edge of the paperboard is being slit at a desired width, The apparatus is adapted to clamp to the support bars on a corrugator slitter to permit edge folding and sealing during a continuous corrugating process. This mechanism provides dimensional stability in that an edge folding plow and slitter are tied together and mounted by means of spring-loaded double hinges that apply the necessary pressure to the folding edge and permit the apparatus to follow the edge of the sheet when weave occurs.

PATENTEDnm 2s 19?! 3,516,077

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PATENTED B 25 1971 3,616,077

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4 A'ITQJUQQHS' CORRUGATED PAPERBOARD EDGE SEALING AND SLITTING APPARATUS BACKGROUND OF THE INVENTION This invention relates to novel apparatus for providing a dimensionally stable sheet of corrugated paperboard wherein one edge of the paperboard is sealed by having an extended portion of one of the liner layers folded over the edge of the fluted medium and the other liner layer and adhesively sealed to the other liner layer while the opposite edge of the paperboard is being slit at a desired width.

The process of using an extended single face liner and wrapping the extended edge around the fluted portion and opposite liner to form a sealed end on a sheet of corrugated paperboard is generally known in the prior art. This process is the outgrowth of the increasing demand that has been experienced in recent years for relatively inexpensive containers suitable for the bulk shipment of chemicals in pellet or powder form, synthetic rubber, and various other commodities. With such products, it has been necessary to insure adequate pro tection of these products from paperboard, chemical or particle contamination. In the prior art, it has been necessary to conduct this folding and sealing operation at a location separate from the corrugating operation. In addition, due to the inherent weave which occurs on modern corrugating apparatus, it has been very difficult with currently available equipment to perform this folding and sealing operation while simultaneously slitting the opposite edge. Thus, the use of this process in the prior art has necessitated transporting the corrugated paperboard sheets to a separate operating station for the sealing and folding procedure and then returning them to a slitter device where sizing of the resulting sealed paperboard sheet is accomplished. Hence, the production of a corrugated aperboard sheet wherein one edge is folded and sealed has to date been a rather timeconsuming and expensive procedure.

It is, therefore, an object of this invention to provide apparatus adapted to be used in a continuous corrugating process which can simultaneously fold and seal one edge of a paperboard sheet while slitting the opposite edge to a desired width.

SUMMARY OF THE INVENTION To accomplish this objective, this invention provides an edge folding plow and a slitter which are tied together and mounted on spring-loaded double hinges which apply the necessary pressure to the folding edge and permit the apparatus to follow the edge of the web when weave occurs. The apparatus of this invention is adapted to clamp to the support bars on a corrugator slitter to permit edge folding and sealing during a continuous corrugating process.

Thus, the unique apparatus of this invention accomplishes folding and sealing of one edge and slitting of the opposite edge of a sheet of corrugated paperboard while maintaining dimensional stability of the sheet as it comes off a continuous corrugator.

Other objects, features, and advantages of the subject invention will become obvious to those skilled in the art to which it pertains upon reference to the following detailed description and the drawings depicting the preferred embodiment of the invention.

In the drawings:

FIG. 1 is a perspective view of he novel apparatus of this invention.

FIG. 2 is a schematic perspective view of a sheet of corrugated paperboard prior to having its extended liner layer folded and sealed in accordance with this invention.

FIG. 3 is a schematic perspective view of the paperboard sheet of FIG. 2 with its extended inner layer in a partially folded and sealed condition.

FIG. 4 is a schematic perspective view of the paperboard sheet of FIG. 3 with its extended liner layer in a completely folded and sealed condition.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION Referring first to FIG. 1, it can be seen that the novel apparatus of this invention, generally indicated by the numeral 10, is utilized to perform sealing and slitting functions on a sheet of corrugated paperboard 12. The sheet of corrugated paperboard 12 may be any of the standard types having a pair of liner layers 14 and 16 separated by and laminated to a corrugated or fluted medium layer 18. Since it is desired in this case to have one edge of the corrugated paperboard 12 sealed, the lower liner layer 16 is formed so as to have an extending portion or margin 20 protruding beyond the edge of the medium layer 18 and the upper liner layer 14. This margin portion 20 is of sufficient size so as to be able to be folded over the medium layer 18 and the upper liner layer 14 and be sealed to the upper liner layer 14 as shown in the sequence of FIGS. 2 through 4.

The apparatus 10 includes as its support structure a pair of beams 22 and 24 which are tied and fixed together at both ends by steel rods 26. The beam 22 has fastened to it a short channel section 28 which serves as a lead-in support structure for the paperboard sheet 12 as it approaches the folding and slitting devices to be described later. Similarly, the beam 24 has fastened to it a channel section 30 which supports the paperboard sheet 12 as it leaves the folding and slitting devices. By means of the beams 22 and 24, the apparatus I0 is adapted to be attached to and supported by slitter support bars 32 on a standard corrugator slitter which is part of a continuous corrugator shown schematically as 33 here. The mounting of the beams 22 and 24 on the slitter support bars 32 permits the incorporation of the novel apparatus 10 of this invention into a continuous corrugating process.

The edge folding and sealing portion of the apparatus 10 includes a ramp surface 34, an edge folding plow 36, and an adhesive dispenser 38, all of which are attached to a first double hinge 40. In addition to being attached "to the double hinge 40, the ramp 34 and edge folding plow 36 are slidingly supported at their rearward end on the right-angle beam 24. The first double hinge 40 is pivotally mounted to right-angle beam 22 at 42 and is spring loaded by means of a tension spring 44 which is attached at its opposite ends to the beam 22 and the double hinge 40, respectively. The tension spring 44 applies the necessary pressure on the edge of the paperboard to facilitate folding of the margin 20 by the edge folding plow 36. Further included in the edge folding and sealing portion of the apparatus 12 is a leaf spring 46 mounted to the first double hinge 40 rearward of the edge folding plow 36 and a number of similar leaf springs 48 mounted to the channel section 30. These leaf springs 46 and 48 provide a holddown function to increase the quality of the adhesive bond between the protruding margin 20 on the lower liner 16 and upper liner 14. It should be understood that a series of rollers could be used in place of the leaf springs.

The slitting portion of the apparatus 10 includes a trim knife slitter device 50 which is attached to a second double hinge 52. The slitter device 50 is also supported at its rearward edge by a supporting bar 54 which is slidably positioned on beam 24. The second double hinge 52 is pivotally mounted to beam 22 at 56.

An important feature of this invention is the fixing together of the first and second double hinges, 40 and 52, by means of a pair of tie rods 58. The tie rods 58 fix the distance between the edge folding plow 36 and the slitter 50 and eliminate any movement of these devices relative to each other. Thus, whenever the spring-loaded first double hinge 40 holding the folding and sealing mechanism move relative to the beams 22 and 24, the second double hinge 52 and the slitter 50 move an over the ramp surface 34 into contact with the edge folding plow 36. Since the plow 36 is mounted on spring-loaded double hinge 40, it is able to move laterally to align itself with the edge of paperboard sheet 12. And, since hinges 40 and 52 are tied together by rods 58, any adjustment in position by plow 36 results in an identical movement by slitter 50. Thus, this mobility of the plow 36 and slitter 50 automatically compensates for any misalignment or weave in the paperboard sheet 12 as it leaves the continuous corrugator and insures dimensional stability in the resulting corrugated paperboard sheet.

The edge folding and sealing sequence can best be understood by reference to FIGS. 2 through 4 in conjunction with the apparatus shown in FIG. 1. As the paperboard sheet contacts edge folding plow 36, a suitable adhesive 60 is applied from adhesive dispenser 38 on to the upper surface of liner layer 14.

The extended portion or margin is folded up over on to the top surface of liner layer 14 as the paperboard sheet 12 passes under the edge folding plow 36. After passing under the plow 36, the paperboard sheet 12 with its edge folded and sealed (as shown in FIG. 4) comes into contact with the series of lead springs 46 and 48, which apply pressure to the folded over margin 20 to insure a good bond between the margin 20 and the liner layer 14.

As the folding and sealing operation is being performed on the margin-containing edge, the paperboard sheet 12 is being slit to a desired width on its opposite edge by the slitter 50. The width of the resulting paperboard sheet can be varied by adjusting the length of the tie rods 58.

Thus, it should be clear that the subject invention provides novel apparatus which is capable of folding and sealing one edge of a sheet of corrugated paperboard while simultaneously slitting the opposite edge at a desired width. The apparatus of the subject invention is novel for the further reason that it is adapted to compensate for weave in the paperboard web to continuously provide a dimensionally stable sheet.

The dimensionally stable sheet of corrugated paperboard produced by the novel apparatus of this invention has many uses. Since one edge is completely sealed, the corrugated or fluted medium layer is protected from moisture making the sheet suitable for use in high humidity and moisture conditions. A sheet produced on the apparatus of this invention having one end of the flutes sealed and the other end of the flutes open so that the flutes can be filled with a suitable material such as bentonite clay making the sheet useable as an insulating or barrier material.

It should be noted further that the adaptability of the novel apparatus of this invention to be used directly with a continuous corrugator eliminates the necessity in the prior art of removing the paperboard sheet to a separate location for the edge folding and sealing functions.

Although but one embodiment of the subject invention has been shown and described in detail, it should be obvious to those skilled in the art to which it pertains that many changes and modifications may be made thereto without departing from the scope of the invention.

We claim:

1. Apparatus for producing a constant width, continuous web of wrapped edge corrugated paperboard on a conventional corrugating machine wherein said paperboard web includes a fluted medium layer sandwiched between first and second liner layers, the first of said liner layers having an extended edge portion folded over and sealed to the second of said liner layers, said apparatus comprising, in combination:

a fixed frame;

a first double hinge member pivotally mounted to said fixed frame adjacent one edge of said paperboard web;

a second double hinge member pivotally mounted to said fixed frame adjacent an opposite edge of said paperboard web;

connecting means joining said first and second double hinge members for movement together as a unit; biasing means extending between said fixed frame and at least one of said connected first and second double hinge members; edge folding an sealing means mounted on said first double hinge member to continuously fold over and seal said extended edge portion of said first liner layer to the second liner to form a wrapped edge corrugated paperboard web;

and edge slitting means mounted on said second double hinge member to continuously slit said opposite edge of said corrugated paperboard web at a fixed width.

2. Apparatus as set forth in claim 1 wherein said biasing means comprises a tension spring connected at one end to said fixed frame and at the other end to at least one of said connected first and second double hinge members to bias said edge folding and sealing means into following relationship with said one edge of said corrugated paperboard web,

3. Apparatus as set forth in claim 2 wherein said edge folding and sealing means further includes an adhesive dispenser adapted to apply an adhesive substance to the second of said liner layers prior to the folding of said extended edge portion of the first of said liner layers into surface contact with the second of said liner layers and an edge folding plow adapted to fold said extending edge portion of said first liner layer over into surface contact with the second of said liner layers. 

2. Apparatus as set forth in claim 1 wherein said biasing means comprises a tension spring connected at one end to said fixed frame and at the other end to at least one of said connected first and second double hinge members to bias said edge folding and sealing means into following relationship with said one edge of said corrugated paperboard web.
 3. Apparatus as set forth in claim 2 wherein said edge folding and sealing means further includes an adhesive dispenser adapted to apply an adhesive substance to the second of said liner layers prior to the folding of said extended edge portion of the first of said liner layers into surface contact with the second of said liner layers and an edge folding plow adapted to fold said extending edge portion of said first liner layer over into surface contact with the second of said liner layers. 